<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

 <html xmlns="http://www.w3.org/1999/xhtml">

<head>

       <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />

       <title>??</title>

<style type="text/css">

              *{margin:0;padding:0;}

           .layer1{width:100%; height:200px; }

                 .layer1-1{width:30%; height:200px; background:pink;float:left}  

                 .layer1-2{width:30%; height:200px; background:blue;float:left}

                 .layer1-3{width:30%; height:200px; background:yellow;float:left}

 

          .layer2{width:90%; height:200px; background:green;color:blue;text-align:center;text-align:center;}

          .layer3{
	width:90%;
	height:200px;
	color:white;
	text-align:center;
	background-color: #F60;
}  

          .layer4{clear:both;}          

       </style>

    </head>

 <body>

       <div class="layer1">

            <div class="layer1-1"></div>

            <div class="layer1-2"></div>

            <div class="layer1-3"></div>

            <div class="layer4"></div>

       </div>    

 <div class="layer2">

    </div>    

    <div class="layer3"></div>

 </body>

 </html>
